cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A193871 Square array T(n,k) = k^n - k + 1 read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 7, 7, 1, 1, 15, 25, 13, 1, 1, 31, 79, 61, 21, 1, 1, 63, 241, 253, 121, 31, 1, 1, 127, 727, 1021, 621, 211, 43, 1, 1, 255, 2185, 4093, 3121, 1291, 337, 57, 1, 1, 511, 6559, 16381, 15621, 7771, 2395, 505, 73, 1, 1, 1023, 19681, 65533, 78121, 46651, 16801, 4089, 721, 91, 1
Offset: 1

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Author

Omar E. Pol, Aug 21 2011

Keywords

Comments

The columns give 1^n-0, 2^n-1, 3^n-2, 4^n-3, 5^n-4, etc.
The main diagonal gives A006091, which is a sequence related to the famous "coconuts" problem.

Examples

			Array begins:
  1,   1,    1,     1,     1,    1,    1,   1,   1,   1
  1,   3,    7,    13,    21,   31,   43,  57,  73
  1,   7,   25,    61,   121,  211,  337, 505
  1,  15,   79,   253,   621, 1291, 2395
  1,  31,  241,  1021,  3121, 7771
  1,  63,  727,  4093, 15621
  1, 127, 2185, 16381
  1, 255, 6559
  1, 511
  1
		

Crossrefs

Row 1: A000012. Rows 2,3: A002061, A061600 but both without repetitions.
Cf. A276135.

Programs

  • Mathematica
    Table[k^# - k + 1 &[n - k + 1], {n, 11}, {k, n}] // Flatten (* Michael De Vlieger, Nov 16 2016 *)

A253209 a(n) = 6^n + 5.

Original entry on oeis.org

6, 11, 41, 221, 1301, 7781, 46661, 279941, 1679621, 10077701, 60466181, 362797061, 2176782341, 13060694021, 78364164101, 470184984581, 2821109907461, 16926659444741, 101559956668421, 609359740010501, 3656158440062981, 21936950640377861, 131621703842267141
Offset: 0

Views

Author

Vincenzo Librandi, Dec 29 2014

Keywords

Comments

Subsequence of A226814.

Crossrefs

Cf. similar sequences listed in A253208.

Programs

  • Magma
    [6^n+5: n in [0..30]];
  • Mathematica
    Table[6^n + 5, {n, 0, 30}]

Formula

G.f.: (6 - 31*x) / ((1 - x)*(1 - 6*x)).
a(n) = 7*a(n-1) - 6*a(n-2) for n>1.
Showing 1-2 of 2 results.